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The following page has been changed by breed:
http://wiki.apache.org/pig/PigExercise2

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  Now we are going to write a shell script to permute the names into a list of 
userids with ages. We will invoke it using: (Note, this time those quotes need 
to be back quotes.)
  
  {{{
- users = stream a through `randid.sh` as (user, age);
+ users = stream sn through `randid.sh` as (user, age);
  }}}
  
  randid.sh will get the contents of 'singlenames' in standard in. Things 
written to stdout will be taken as output tuples. By default tuples are 
separated by \n and fields by \t. If you'd rather skip the pain of writing the 
randid.sh script, here is an example:
@@ -52, +52 @@

  Okay now we have our users, lets generate the pages dataset. We want to 
generate a bunch of page requests for each user, so we will make a UDF that 
takes in tuples from users and generate fake traffic:
  
  {{{
- pages = foreach a generate flatten(pig.example.GenerateClicks(*)) as (user, 
url);
+ pages = foreach sn generate flatten(pig.example.GenerateClicks(*)) as (user, 
url);
  }}}
  
  GenerateClicks needs to extend EvalFunc<DataBag>. Here is an example 
implementation:

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